Vacuum-airtight arrangement for endless belt filter



Sept 17, 1963 ElTARo KAsUYA VACUUM-AIRTIGHT ARRANGEMENT FOR ENDLESS BELT FILTER Filed DBG. '7, 1960 2 Sheets-Sheet 1 INVENTOR.

"u ald F/HE l-III Sept. i7, 1963 ElTARo KAsUYA 3,104,223

VACUUM-AIRTIGHT ARRANGEMENT FOR ENDLEss BELT FILTER Filed Deo. '7, 1960 2 Sheets-Sheet 2 IN V EN TOR.

United States Patent C 3,104,223 VACUUM-AIRTIGHT ARRANGEMENT FR ENDLESS BELT FILTER Eitaro Kasuya, Tokyo, Japan, assignor to Nissan Chem- .ical Industries, Ltd., Tokyo, Japan, a corporation f apan Filed Dec. 7, 1960, Ser. No. 74,281 Claims priority, application Japan Dec. 12, 1959 6 Claims. (Cl. 210-400) This invention relates to a new endless belt filter. The endless belt filter of known type has been consisted yof a. conveyor belt driven Iby two rotating drums arranged at front and back and la suction box which contacts with the under-tace of the belt. The belt is lined with lilter cloth and conveys sub-stances on the cloth, while iiltering and washing successively, and the iiltrate is dnawn into the suction box 4which is connected to a vacuum pump and a dischar-ge pipe.

The under-face of the conveyor belt is in contact with the upper part of the suction box, and the belt slides on it while maintaining vacuum-in the suction box. Since the sliding face bears the load of belt, it is essential that arrangement is so made as to operate this part smoothly.

The construction of this sliding part has been hitherto 'given out in Japanese patent lapplication publication No. 2,359/ 1935, Japanese utility model applica-tion publication'Nos. 13,880/1938 and 17,038/1938.

The present invention relates to a vacuum, air-tight arrangement for endless belt filter 'driven by rotary drums, in which tight contact and smooth sliding action between a .conveyor belt 'and the upper face of a suction box is attained by means of a system entirely different .from those previously known, characterized in that an Iair-tight strip made of oil saturated soft rubber is inserted between the under-face of the conveyor belt and the upper part of the suction box, and supported on van air spring.

The objem of the invention is to provide an arnangement which produces a vacuum tight connection Ibetween conveyor belt tand suction box with la of pressure on their Contact faces thereby protecting the sliding faces from wear.

The arrangement of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of an endless belt filter equipped with the vacuum-tight arrangement of the present invention, showing the manner of its fitting;

FIG. 2 is ya cross sectional view of the arrangement taken along the line A-B in FIG. l;

FIG. 3 is a plan view of an airtight cushion shown in FIG. 2; `and FIG. 4 is across sectional view of the yair-tight cushion taken along the lline C-D in FIG. 3.

In FIG. l, a conveyor belt 1 is driven by rotary drums 3 to slide on the upper face of an airtight strip 6. The

air-tight strip is mounted on the upper part of a suction box 5 Iand supported on air springs 15. The suction box is connected by a rubber hose 19 to a vacuum pump.

In FIG. 2, a hole 4 on the conveyor belt is tor extnaction of iiltrate. A iilter cloth 18 and a perforated belt 17 supporting said filter cloth 18 are laid together on the conveyor belt, and the liquid to be filtered 2 is carried thereon. The air-tight strip is litted in a groove 13 arranged in the upper part of the suction box, and lubricating oil is supplied into `grooves of the upper tace of the air-tight strip through oil pipe 14 provided at the side wall. As the air-tight strip is supported on air springs 15 and by the regulation of lair pressure thereto, the pressure between the upper tace of the air-tight strip and the under-face of the conveyor belt can freely be adjusted. A pipe 16 for supplying compressed -air into the air 3,104,223 Patented Sept. 17, 1963 spring is connected to an air compressor and a pressure controlling valve.

The upper face of the air-tight strip, as shown in FIG. 3, is covered with soft rubber 8 on which a number of oil grooves 7 are provided for retaining lubricant.

FIG. 4 gives a detailed construction of the above 1arnangement, show-ing that lubricant comes through oil pipe to cil holes 1.1 and 12, thence to grooves 7.

'I'lie .interior of the -air-tight strip is enclosed by la soft rubber casing 8 and conatins ya sponge like material 9 for cushioning land ya metallic reinforcement 101.

lThe special feature of this invention may be itemized las tollows:

(a) By the use of air springs for bringing together of contact faces, the determination of correct pressure for the maintenance of vacuum, can be easily -attained with the help of pressure gauge indication. This, in comparison with the use of Ian ordinary metalli-c spring, has the advantage in that there is no possibility of over-pressure and it minimizes the ywear of contact faces.

(b) The upper face of the air-tight strip being composed of soft rubber (hardness number 45-50 in JIS (Japanese Industrial Standard) 4and the under-face of the conveyor belt of rubber of hardness number in JIS, practically all the wear due to sliding is eliminated. The soft rubber forming the upper face of the `air-tight strip should be regarded as wearing part, so that the rubber is changed for a new lone at a suitable interval say, every two months.

(c) The fact that the sliding faces are provided with oil grooves to permit a :constant oil supply to the zfaces, reduces the frictional resistance to a minimum and prevents excess loading of belt. On this score, the present system has the advantage over the system (see patent applicati-on publication No. 9,947/ 1953) of using la sliding belt.

(d) The procedure of changing the air-tight strip 6 by removing it from the groove 13 is an extremely simple matter. The worn strip may be used repeatedly by reprocessing the upper surface with new rubber lining. On this point, it is less expensive than the system of sliding belt (patent application publication No. 9,947/ 1953).

What I claim is:

l. Filtering apparatus of the band filter type having -an endless belt and a plurali-ty of suction boxes, the endless belt passing over the suction boxes which exert suction forces thereon to cause filtration of material supported on .said belt, the suction boxes each comprising a rectangular body having central suction openings and la marginal element supporting the endless -belt in slidable relation, said marginal element having a rectangular cross-section and comprising Ia hollow flexible casing having anv upper surface for supporting the belt thereon, said upper surfacebeing provided with la plurality of grooves therein, means for feeding lubricant to said grooves whereby fricd tional resistance between the endless belt and `the suction boxes is minimized, said marginal elements further comprising sponge means within 'the hollow casing beneath,

' into contact with the belt to maintain au `airtight relation therebetween.

2. Filtering apparatus as claimed in claim l wherein said hollow llexible casing is rubber.

3. Filtering apparatus as claimed in claim l wherein said means for feeding lubricant to said vgrooves comprises a lubricationV conduit in said marginal element extending externally thereof -and passing through the metallic reinforce-ment means and the sponge means and into 3,104,223 3 4 communication with the grooves in the upper surface of 6. Filtering apparatus as claimed in` claim 1 wherein the casing. said marginal elements have` a substantially square cross 4. Apparatus as claimed in claim 2 wherein the air section. spring means includes 'a hollow casing adapted to lbe connected to a source of air which can be pressure regu- 5 References Cited in the 51e 0f this Patent lated whereby the pressure between Ithe endless belt and UNITED STATES PATENTS the suction boxes can be adjusted.

5. Filtering apparatus as claimed -in claim 1 wherein ggdan gg each rectangular body is removably supported in the 2561282 Lemer July 17 1951 associated suction box, said hollow flexible casing of the 10 5683420 Thoms-I; Sept 1.3: 1951 mavginal element being removable and thereby replaceable when the casing becomes worn. 

1. FILTERING APPARATUS OF THE BAND FILTER TYPE HAVING AN ENDLESS BELT AND A PLURALITY OF SUCTION BOXES, THE ENDLESS BELT PASSING OVER THE SUCTION BOXES WHICH EXERT SUCTION FORCES THEREON TO CAUSE FILTRATION OF MATERIAL SUPPORTED ON SAID BELT, THE SUCTION BOXES COMPRISING A RECTANGULAR BODY HAVING CENTRAL SUCTION OPENINGS AND A MARGINAL ELEMENT SUPPORTING THE ENDLESS BELT IN SLIDABLE RELATION, SAID MARGINAL ELEMENT HAVING A RECTANGULAR CROSS-SECTION AND COMPRISING A HOLLOW FLEXIBLE CASING HAVING AN UPPER SURFACE FOR SUPPORTING THE BELT THEREON, SAID UPPER SURFACE BEING PROVIDED WITH A PLURALITY OF GROOVES THEREIN, 